I do remember reading the police aren't paid enough to get by without money under the table. They buy their own bullets, have to buy their own air conditioners in cars, and whatever else. Same up and down the line, judges, what have you. Everyone is on the take, it's presumed everyone is, and it costs society a lot more than paying them a living wage and keeping them in line.
But this is an ongoing problem that's gotten worse, their public hates the cartels for the violence, but they've been unable to at least get the local police in charge of their own states? Something is off with their leadership from the top down. Either than, or maybe they just need a hug!.